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FACT SHEET: Polycythemia (also known as “erythrocytosis”; includes “polycythemia vera” [PV; also known as “primary polycythemia”, “polycythemia rubra vera”, “erythemia”, “Osler-Vaquez disease”, “splenomegalic polycythemia”, and “erythrocytosis megalosplenica”], “secondary polycythemia”, and “relative polycythemia” [includes “stress polycythemia”])

Date of Publication: June 20, 2019

Note: The therapeutic modalities of chemotherapy, radiation therapy, and hematopoietic cell transplantation are addressed in detail in separate fact sheets.

Is the initiation of non-invasive dental hygiene procedures* contra-indicated?

  • Unlikely, but depends on severity (and proliferative versus “spent” phase in polycythemia vera), severity of complications arising from treatment (e.g., chemotherapy for PV), and procedure being contemplated.

Is medical consult advised?

  • Yes, if the patient/client is undergoing chemotherapy and has, or is suspected to have, certain oral conditions or systemic manifestations.
  • Yes, if the patient/client is about to undergo, or is undergoing, radiation therapy.
  • Yes, if the patient/client appears debilitated.
  • Yes, if undiagnosed or suboptimally treated polycythemia is suspected.

Is the initiation of invasive dental hygiene procedures contra-indicated?**

  • Yes. This is a blood disorder as per Ontario Regulation 501/07 pursuant to the Dental Hygiene Act, 1991.
  • Polycythemia may affect appropriateness or safety, and scaling and root planing, including curetting of surrounding tissue, are contraindicated until the patient/client is medically cleared. Other possible contra-indications include active chemotherapy and/or radiation therapy (for polycythemia vera), as well as significant immunosuppression and/or bleeding disorder (e.g., thrombocytopenia or dysfunctional platelets) resulting from the disease itself and/or its treatment.

Is medical consult advised?

  • See above. Additionally:
    • advice about excessive bleeding and increased risk of blood clots should be sought (from hematologist or primary care physician);
    • precautionary measures, such as blood tests, may be indicated before oral healthcare is undertaken; and
    • pre- and post-chemotherapy medical (e.g., from oncologist or primary care physician) and/or dental consultation is often warranted.

Is medical clearance required?

  • Yes, if polycythemia has been diagnosed or is suspected.
  • Yes, if the patient/client is undergoing chemotherapy (for polycythemia vera) or radiotherapy (as a prelude to hematopoietic cell transplantation in PV).
  • Yes, if patient/client has spleen damage or has had a splenectomy (resulting in compromised immunity and thus increased risk for serious infections).
  • Yes, if leukopenia (and hence possible immunosuppression) exists or is suspected in patient/client in the “spent phase” of PV.
  • Yes, if thrombocytopenia or decreased platelet function exists or is suspected (particularly in polycythemia vera).
  • Yes, if anemia has been diagnosed or is suspected (particularly in the “spent” phase of PV).
  • Medical clearance may also be required if patient/client is being treated with medications or treatment modalities associated with immunosuppression +/- increased risk of infection (e.g., ruxolitinib, fedratinib, and busulfan in the management of PV).

Is antibiotic prophylaxis required?

  • Possibly, for some patients/clients according to [1] blood indices (e.g., low neutrophil count) that indicate immunosuppression from the disease itself (e.g., “spent” phase of PV) and/or from chemotherapy and/or radiation therapy1 and/or medications associated with immunosuppression and/or [2] drug delivery mechanism (e.g., in-dwelling central venous catheters).
  • Additionally, patients/clients who have had a splenectomy often take ongoing antibiotic prophylaxis. While antibiotic prophylaxis is not routinely indicated prior to dental procedures for asplenic adult dental patients without risk factors, it should be considered for young children, immunocompromised patients with underlying causative disease (such as “spent” phase of polycythemia vera), or any patient/client during the first 3 years after a splenectomy.

Is postponing treatment advised?

  • Possibly, depending on blood indices (which indicate degree of polycythemia, or leukopenia and/or thrombocytopenia and/or anemia in “spent phase” of PV or related to chemotherapy or radiation therapy). Elective invasive procedures should be deferred until after chemo- or radiation-induced immunosuppression ceases.
  • In the case of hematopoietic cell transplantation, elective oral procedures, including scaling and polishing, should be delayed until the patient/client’s immune system returns to normal; typically, this takes 6 to 12 months post-transplantation.

Oral management implications

  • Refer to Chemotherapy, Radiation Therapy, Hematopoietic Cell Transplantation, and Xerostomia fact sheets, as applicable.
  • While oral lesions usually do not require local treatment in patients/clients with polycythemia vera, excessive bleeding may occur after invasive procedures. Thus, cautious use of procedures, coupled with post-procedure observation and advice, is indicated.
  • In PV, parenteral (i.e., intravenous and intramuscular) sedation techniques are relatively contraindicated because of increased risk of excessive bleeding and thrombosis. Furthermore, outpatient general anaesthesia (GA) is also relatively contraindicated; hospitalization and treatment as an inpatient should be considered if GA is contemplated.
  • Most patients/clients with PV take low-dose aspirin to reduce the risk of blood clots.
  • In the absence of medical advice to the contrary, non-steroidal anti-inflammatory medications (e.g., ibuprofen) should be avoided for pain management, because of the risks of gastrointestinal ulceration and interference with the anti-clotting effect of low-dose aspirin.
  • Preventive oral healthcare is important to avoid dental emergencies in patients/clients with polycythemia.

Oral manifestations

  • Refer also to Chemotherapy, Radiation Therapy, Hematopoietic Cell Transplantation, and Xerostomia fact sheets for details regarding cancer treatment-related dry mouth, caries, mucositis, gingival bleeding, dysgeusia, infections, and periodontitis.
  • Abnormalities in the oral mucosa result from an increase in the number of circulating red blood cells (RBCs), impaired blood flow, and thrombocytopenia.
  • The oral mucosa may appear deep red to purple, and the gingiva may be edematous. Purplish or red areas may also appear on the cheeks, lips, and tongue.
  • The gingiva may bleed easily (and spontaneously), and submucosal petechiae, ecchymoses, and hematomas may be present.
  • Red skin colour may be noted in the face.
  • Xerostomia may occur secondary to interferon use in polycythemia vera.
  • Ulcerations, sores, and white spots in the mouth, as well as sores on the lips, can occur with hydroxyurea treatment. Oral mucosal hyperpigmentation has also been linked to hydroxyurea therapy.

Related signs and symptoms

  • Polycythemia is an increase in the total red blood cell mass in the blood. The increase can be either absolute or relative.2

Polycythemia vera

  • This is a form of blood cancer. Uncontrolled proliferation of bone marrow stem cells results in an abnormally elevated number of circulating RBCs. The number of platelets may also initially be higher in number than normal (with attendant adverse effects), as may the number of white blood cells (usually without significant effects). In the “spent” or “burnout” phase that may eventually occur, the bone marrow is replaced by scar tissue (myelofibrosis), resulting in lower production of functioning red cells (anemia), white cells (leukopenia), and platelets (thrombocytopenia).
  • Primary polycythemia3 has a prevalence of about 22 persons per 100,000 population, equating to about 3,200 affected individuals in Ontario and 8,400 in Canada.
  • This chronic myeloproliferative disorder is usually associated with a gene mutation, the cause of which is unknown. The average age of onset is between 60 and 65 years of age, with diagnosis uncommon in persons aged less than 40 years. Caucasian males are affected at a higher rate.
  • PV usually develops slowly, and many persons have no or few symptoms related to the disease at the time of diagnosis (which may first be detected through an incidental complete blood count test).
  • Signs/symptoms in the proliferative phase include: headache; dizziness; pruritus (especially after exposure to warm water); numbness, tingling, or burning pain in the extremities; fatigue; shortness of breath (particularly when lying down); excessive sweating (especially at night); visual disturbances; tinnitus; bluish or reddish skin; full feeling in the left upper abdomen (due to splenomegaly); painful, swollen joints (due to gout4); and severe back/flank pain (due to kidney stones).
  • Increased red blood cell mass leads to hyperviscosity and hence impaired blood flow and vascular stasis, which in turn contributes to the formation of thrombi formation that can disrupt blood supply to the heart (myocardial infarction), brain (stroke), lungs (pulmonary embolism) and peripheral vessels (deep venous thrombosis [DVT]).
  • Dysfunctional platelets (in the proliferative phase) or thrombocytopenia (in the “spent” phase) may result in bleeding sequelae such as petechiae, ecchymoses, nosebleeds, intestinal bleeding5, menorrhagia6, or bleeding from the respiratory tract.
  • Complications of PV may include acute myelogenous leukemia (AML), hypertension, and heart failure.
  • Prognosis for untreated patients/clients is poor, with survival time ranging from 6 to 18 months after diagnosis. However, phlebotomy extends average survival time to 12 years. Acute leukemia accounts for 5% of deaths.

Secondary polycythemia

  • The increase in RBCs is usually caused by physiologic response to chronic hypoxemia7. This can result from living at high altitudes, chronic heart disease, chronic obstructive pulmonary disease, sleep apnea, and an elevation in carboxyhemoglobin (e.g., due to carbon monoxide inhalation from smoking).
  • Other factors that cause increased levels of erythropoietin and hence red blood cell production include tumours of the kidney or liver, as well as abuse of anabolic steroids or exogenous erythropoietin by athletes.
  • Patients/clients with hematocrits higher than 60% to 65%8 may experience impaired alertness, headaches, dizziness, and decreased exercise tolerance. Similar to polycythemia vera, there may be increased risk of thrombosis, myocardial infarction, and stroke.

Relative polycythemia

  • Decreased plasma volume results in a relative, not absolute, increase in RBCs. Acute causes include decreased fluid intake, vomiting, diarrhea, excessive sweating, and diuretic use.
  • A chronic form is known as “stress polycythemia”, which predominately affects middle-aged Caucasian men who are under physiologic stress, hypertensive, overweight, and heavy smokers. Risk of myocardial infarction and stroke is increased.

References and sources of more detailed information

Date: November 10, 2018
Revised: June 2, 2023


1 particularly total body irradiation for bone marrow/stem cell transplantation purposes
2 Diagnosis involves laboratory tests such as hemoglobin and hematocrit; bone marrow biopsy, erythropoietin level, and genetic testing may also be utilized. Treatment depends on the type of polycythemia, and it may include elimination of causative factors (in secondary polycythemia); chemotherapy or hematopoietic cell transplantation (in polycythemia vera); phlebotomy (bloodletting); medications to suppress production of, or circulating numbers of, various blood cells (e.g., hydroxyurea, anagrelide, interferon, and ruxolitinib); and drugs to reduce the risk of blood clots (e.g., aspirin).
3 While PV is the best known form of primary polycythemia, other rare types include primary familial and congenital polycythemia (PFCP), Chuvash polycythemia, and disordered hypoxia sensing due to several very rare mutations.
4 Gout is a form of arthritis caused by excess uric acid in the bloodstream. Excess uric acid can result from increased turnover of red blood cells, which can also contribute to kidney stone formation.
5 Bleeding from the upper gastrointestinal tract can result in melena (black tarry stools).
6 menorrhagia = abnormally heavy menstrual bleeding
7 A chronic decrease in the oxygen level of the blood triggers increased production of erythropoietin by the kidneys, which results in increased production of RBCs.
8 Hematocrit is the ratio of volume of red blood cells to the total volume of blood. Normal hematocrit level is approximately 39% to 50% for men and 35% to 45% for women.

* Includes oral hygiene instruction, fitting a mouth guard, taking an impression, etc.
** Ontario Regulation 501/07 made under the Dental Hygiene Act, 1991. Invasive dental hygiene procedures are scaling teeth and root planing, including curetting surrounding tissue.